Safety alarm for gas burners



Mh 37 19355 w. Moi-mm1 SAFETY ALARM FOR GAS BUHNERS Filed April 24, 1950P ing, l

Patented Mar. 3, 1936 UNITED STATES PATENT OFFICE SAFETY ALARM FOR GASBURNERS William Mohlman, Eggertsville, N. Y. Application April 24, 1930,Serial No. 446,842

1 Claim.

This invention relates to safety alarms for gas burners.

One of the objects of this invention is the pro-- vision of improvedmeans associated with a gas burner or burners to cause a signal, eitheraudible or visible, to be given in the event the gas pressure fails andextinguishes all burners.

Another object of my invention is to provide, in association with apilot light and the main burner or burners of a stove, heater, and thelike, means to automatically light the main burner or burners in theevent that the latter are acci. dentally blown out and to prevent theescape of gas from the main burner or burners in the event that a childturns off the gas and playfully turns the gas on again, or in the eventthe gas is accidentally turned on after having been turned o.

A still further object is to provide a normally openthermostatically-controlled circuit closer in association with the pilotlight; said circuit closer being of novel construction and serving toestablish an electric circuit in the event of the pilot light becomingextinguished.

With the above and other objects in view to Q5 appear hereinafter, myinvention consists in the novel features of construction, and in thearrangement and combination of parts to be hereinafter described, andmore particularly pointed out in the subjoined claims.

In the drawings:

Fig. l is a plan View of a four-burner stove; part of the top beingbroken away to illustrate the main burners, the location and associationof the pilot-burner thereto, and other parts of my invention in one ofthe forms now considered desirable.

Fig. 2 is an enlarged vertic-al section through the pilot-burner andassociated parts, taken on line 2-2, Fig. 1.

4o Fig. 3 is a horizontal section taken on line 3--3,

Fig. 2.

Fig. 4 is an enlarged vertical section taken on line 4-4, Fig. 1,looking toward the left.

V Fig. 5 is a plan view of the control valve, part 4.5 of the regulatingvalve and a portion of the gas supply pipe leading to the pilot-burner.

Fig. 6 is a horizontal section taken on line 6-6, Fig. 4. 1

Fig. '7 is an enlarged section taken on line 1-1,

50 Fig. 1.

Y Fig. 8 is a modification of my invention.

In the particular application of my invention shown in the drawings, thenumeral I0 designates a kitchen stove having the usual top, shown 5 5partly broken away, but invariably provided with openings .directly overthe burners adapted to be closed with lids or griddles. The mainburners, designated Il are therefore exposed, as well as various partsadjacent thereto to better illustrate this invention. Each of saidburners has 5 an individual gas-pipe I2 connected therewith, so thatthey may be lighted 4at will. The usual air-mixer I3 is connected toeach pipe and gascocks I4 connected to the gas supply pipe I5 projectinto vthe air-mixers in the usual way. 10

, Arranged equi-distantly between the main burners IIis a pilot burnerI6 which is enclosed in a casing I1. This casing has a top wall I8, asurrounding or peripheral wall I9 and a bottom 20 through which a gaspipe 2l extends from 15 the gas supply pipe I5, the pilot-burner I6being threaded onto the inwardly-extending portion of pipe 2 I, which isimmovably secured in said bottom by nuts 22, 23 applied thereto atopposite sides of the bottom. The pilot-burner may be 20 of anyconstruction and is designed to consume the gasissuing therefrom in theform of a steady comparatively small ame. The bottom of the casing I1 isprovided with air openings 24 and the surrounding or periph- 25 eralwall I9 also has air openings 25. The necessary air to maintain thepilot flame may, however, be lfurnished in any other approved manner.AThe main burners I I have safety lighter-pipes orconduits 26 formedintegrally therewith, or 30 connected thereto as shown in Fig. 8. Saidsafety lighter pipes are perforated at intervals along their length, asat 21, and extend into the air openings 25 in pilot-burner casing I1,their outer ends ,terminating in close proximity to the pilot- 35burner. The purpose of these safety lighterpipes is to conduct gas fromthe main burners to the name of the pilot-burner, and they may thereforebe disconnected from the main burners and arranged in any manner whichwill insure the passage of the gas from the main burners to thepilot-,burner and the conveying of a flame from thepilot-burner back tothe gas escaping directly from the burners. While I consider anymeanssuitable to accomplish such action as falling fully within thescope of the appended claims, Iv have found the gas and flame-conveyinglmeans shown and described very effectual. s Pipe 2I supplying gas to thepilot-burner has a regulating valve 28 therein provided with a 50tapering port 29, opened to any desired degree by a needle valve 30threaded through the casing of the valve and having its pointed endentering saidport to provide for the passage of the ydesired quantity ofgas therethrough, de-

pending on the size of the pilot ame required, and at times on the gaspressure.

In pipe 2| there is also arranged a shut-olf control valve 3|. Thisvalve is shown between the regulating valve 28 and the gas supply pipe5, but may be located between the regulating valve and the pilot burner,if desired.

Carried by and insulated from the surrounding or peripheral wall I9, oras it may be termed, the side wall of the pilot burner casing, is abinding post 32 which carries a xed electrical contact 33. A secondbinding post 34 is carried by and insulated from said side wall I9 andhas electrical connection with a movable contact 35. In the form shown,said Amovable contact is carried by a vertically-disposed arm 36pivotally and electrically secured at a point between its ends to theinner end of the 'binding post 34 and having its lower end enlarged toserve as a weight tending to swing the upper end thereof, and moreparticularly the contact 35 at the upper end thereof, in contact withthe fixed contact 33, except when prevented by the heat of the pilotflame, which is utilized for such purpose. The parts just described forma circuit closer. Separation of the contacts 33 and 35 is accomplishedby means of a thermostatic device which, in the form shown is a slenderrod or member 3`| located over the pilotburner and horizontally disposedso that the pilot flame plays thereagainst, or at least so that the heatfrom the pilot flame Will be effective thereon.

'I'his thermostatic rod or member, of course, possesses the qualities ofexpanding under heat and contracting when cooled, and it is adjustablyarranged in the side wall I9 of the pilotburner casing and insulatedtherefrom. For this purpose the outer portion of said rod or member isenlarged and screw threaded, as at 38, intoan insulating bushing 39secured in said side Wall in any suitable manner, and it has a knurledhead 40 at its outer end for conveniently adjusting the rod to bring theinner end thereof in proper relation to the movable or pivotal contactarm 36, so as to allow the contact 35 of said arm to engage the fixedcontact 33 when the thermostatic rod or member is contracted or cooled,and to cause said movable contact to move away from the fixed contactwhen the thermostatic rod is expanded by the pilot flame or the heattherefrom. Y

This thermostatic rod is normally in engagement with or may be spacedfrom the pivoted contact arm 3B beneath the pivot thereof, and in eithercase, the rod is contracted sufficiently to allow the'pivoted arm 36 toassume a position which will bring the contact 35 thereof in engagementwith the fixed contact. When, therefore the pilot-burner is lighted, theheat therefrom will cause the thermostatic rod to expand and swing thelower weighted end of the contact outwardly, while the upper or contactend swings inwardly away from the fixed contact 33; thus breaking anelectrical circuit which includes a bell 4| or some other suitablesignal or alarm, a battery 42 or other source of current, and suitablecurrent conductors of any kind leadingV to the binding posts 32 and 34.In the drawings, I have shown wires 43, v44, 45 and 45 and the gas pipesl5 and 2| utilized for such purpose.

The shut-off valve 3| in the gas pipe 2| leading to the pilot-burner,comprises a casing 4l and a rotatable valve plug 48 therein throughwhich a passage 49 is formed capable of passing all the gas required atthe pilot-burner, even though said plug is not rotated to its fullextent, and said Valve plug has a stem 53 projecting from its upper endand a laterally extending electrical contact from its periphery which isadapted, under certain conditions, to contact with a segmental electriccontact 52 adjacent the valve casing and secured to an insulationsupport 53 surrounding the inlet branch 55 of the valve casing. Saidsegmental contact has one of the circuit Wires 46 connecting it With thebinding post 34, and is therefore included in the electrical circuit inwhich the signal orV alarm is arranged. The contacts 5| and 52 serve asa circuit breaker.

I have illustrated and described the valve plug of `the shut-off valve3| as provided with a stem, or it may have any other means whereby aseparate or detachable handle or key will be employed for rotating thevalve plug; thus guarding against children shutting off the supply ofgas to the pilot burner and guarding against accidental closing of theshut-off valve.

Normally, the electrical circuit is broken by separation of the contacts5| and 52 associated with the shut-olf valve 3|; and, therefore, whenfirst lighting the pilot light, the valve plug in said shut-olf Valve isonly partially rotated so that the contact 5| projecting from said valveplug will not come into engagement with the segmental contact 52. Thenecessary supply of gas will, however, pass through the passage 49 insaid valve plug and be delivered to the pilot burner to be ignited.Consequently, no signal or alarm Will be given during such actuation ofthe shut-oli^ valve. However, when the flame or heat from the flame ofthe pilot burner has expanded the thermostatic rod 37, it will haveswung the pivoted arm 36 to cause separation of the contacts 33 and 35,after which the valve plug may be fully opened so as to engage thecontact 5| with the contact 52, or in other words, close the circuitbreaker. No alarm, however, will be given, due to the fact that theelectrical circuit is now broken at the thermostatically controlledcircuit closer, and this condition is maintained so long as the gasescaping from the pilot burner is ignited. The size of the iiame at theburner is conveniently regulated by adjusting the needle valve 30 of theregulating valve 28.

If any one or more of the main burners are to be ignited, it is onlynecessary to open the gas cocks 4 in the supply pipes thereof,Vwhereupon the gas will issue from said burners and also travel throughthe lighter pipes or conduits 26, with the result that this gas becomesignited at the pilot light, and as the gas issues from the perforationsin said lighter pipes or conduits, the ame is carried to the mainburners to ignite the gas escaping therefrom. It will therefore beunderstood that, so long as the pilot burner is lighted, the opening ofthe gas cocks controlling the main burners, whether accidental orintentional, will prevent the escape of gas from said burners, as thesafety lighter pipes orconduits 26 Will instantly serve to light theescaping gas at said burners. V j

In the event that the pressure of the gas is reduced to a degree thatthe pilot light becomes extinguished, or if for any other reason gas isnot supplied to the pilot burner, the thermostatic rod will cool andallow the pivoted arm 38 to swing on its pivot and establish an electriccircuit, with the result that the signal or alarm is given.

The control valve 41 is then shut oi until a proper flow of gas is againassured.

It will be apparent from the foregoing, that my invention guards againstasphyxiation, and also explosions in the event of the escaping gas beingaccidentally ignited.

Having thus described my invention, what I claim is:

In a device of the kind described, the combination with a casing, of ahorizontally-disposed thermostatic rod adjustably secured within theperipheral wall of said casing and extending thereinto, twocircuit-connected binding posts secured to said peripheral wall invertical alinement opposite the point of securing said thermostatic rodto said wall, and a vertically-disposed contact element within saidcasing arranged for movement on a horizontal pivot Whose axis isdisposed at a right angle to the axis of said thermostatic rod, saidcontact element being in electrical connection with one of said bindingposts and mounted on said pivot between its ends and having its lowerend weighted and its upper end adapted for contact With the other ofsaid binding posts, said Weighted end causing said element to swing onsaid pivot in one direction into contact with said last-mentionedbinding post when said thermostatic rod is contracted and said contactelement being in engagement at a point beneath its pivot with saidthermostatic rod and being caused to swing in an opposite direction awayfrom said last-mentioned binding post when said thermostatic rod isexpanded.

WILLIAM MOHLMAN.

